Скачать или смотреть Deleting a nasty last character at the end of each line in a file without opening it : In Unix.

How to delete nasty unwanted character present at the end of each line from a file in unix without opening it.
We have used sed command to do that .
there can be a requirement that instead of last one character, there may be more number of characters to be deleted.
So in that case also same command can be used and we just need to replace a . with more number of .
for example if i have to delete last 3 characters from each line at the end in a file.
then we will do as below.
sed -i 's/... $//g' filename
here that $ is representing at the end of line .
each (.) inside command is representing one character.
g is here for replacing globally in the file.
So we are replacing last 3 characters from each line with a null character.
Similarly we can delete last one character from each line inside a file.
so we can use below.
sed -i 's/.$//g' filename
This kind of Questions are sometimes asked in interviews and also i have come across such situations in real world as an IT engineer.
One such situation was like , one of our prod file got corrupted somehow while coming from upstream application.
It was having additional 3 characters at the end of each line of the file.
File was having more than 10k records .
So since we were sure about issue.
So we deleted those nasty characters using this command in few seconds.
Offcourse a backup was taken in advance.
Some people may get confused abd will say we can remove last column using awk or cut.
But this is not necessary that you will always have a pattern and a field separator in between.
What if last 2-3-4 characters are attached to your last string somehow and there is no filed separator in between.
There will be the real use of above sed command.